The loading of missiles, torpedoes, canisters or the like into naval vessels is often a time consuming task. There are two areas of concern for support of missiles: the support of the canister (the item which surrounds and protects the missile), and the support of the missile inside the canister.
For surface ships, a vertical launch structure supports the missile canister. These canisters are locked into the structure using an apparatus to rigidly connect and align the aft end of the canister. This apparatus is called a “Dog-Down”. The Dog Down mechanism is a mechanical screw driven device with tapered wedges. These tapered wedges interface with a female receiver located on the missile canister. The tapered wedges on the Dog Down are drawn together by means of a reverse threaded shaft. This shaft, that passes through the wedges cause the wedges to move toward one another when the shaft is turned. The tapered wedges interface with the female receptacles on the missile canister, pushing the canister downward and sealing against the plenum surface on the launcher. Due to the rigid connection of the canister at the top of the launcher and at the dog-down interface, the entire launcher must be isolated from the ship to ensure shock loads are not transmitted to the missile round. This is a costly solution to the problem. Having a restraint mechanism at the launcher to canister interface would greatly simplify launcher designs and ship compatibility.
For submarines, pads are located on the canister itself for isolation. The launch structure within a submarine is directly connected to a launch tube (no isolation between ship and launcher). Within the launch tube are raised pads whose location coincides with the isolation pads located on the missile canister. The pads, which have tapered-edges and a low friction coating, aid in the installation of the canister in the launch tube. The missile canister is constrained within the launch tube by a connection at the top. Also along the height of the canister are raised rubber pads that interfere with the raised edges in the launch tube, creating an interference fit. This fit provides the lateral support for the canister, and isolates the missile canister from the rest of the launch structure. A hydraulic jack is used to insert the missile canister into the launch tube. Due to the number of pads and the amount of surface area of interference, loads required to insert the missile canister can be as high as 40,000 lbs. In addition to the large loads required to install the missile canister, the time required to mobilize the equipment and insert the canister may be as long as 3 hours per missile. Also, during the hydraulic jacking process, the pads on the missile canister can pop off, jamming between the missile canister and launch tube preventing complete installation.
For missile support, either sabots or snubbers are used to support the missile inside the canister. A sabot is a carrier inside the missile canister that provides support to the missile during shipping and transportation as well as during missile egress. The sabots are usually spring loaded against the missile and upon missile exit from the canister are ejected away from the missile. The sabots create a problem in ripple firing scenarios, since the ejected sabots could be in the flight trajectory of adjacent missiles. Snubbers, on the other hand, are retractable mechanisms within the canister that support the missile during shipping and transportation and fold down out of the way during launch, but always stay inside the canister. Snubbers are mechanical devices that have complex linkages that have reliability issues. In addition, since these linkages are rigid, loads outside the canister are transmitted directly into the missile.
Other known art relies upon passive support, meaning it inflates once and is left alone. Also, because of material selection and support provided to the bladder, other known techniques can only operate at low pressures. The present invention is an active support and can operate at high pressures in excess of 200 pounds per square inch due to the combination of having a support structure and the use of reinforced fabrics. The support structure comprises the recessed groove of our design and supports the top, bottom and back of the bladder. The front of the bladder is supported by the canister or missile.
The inflatable restraint in some fashion addresses all of the shortcomings associated with canister and missile support. The present invention is a constraining/clamping isolator that mitigates the need for having the launch structure entirely isolated. Isolation is occurring locally at the clamping interface by inflatable bladders. Also, when the bladders are deflated, ample clearance exists such that the missile canister no longer has to be hydraulically jacked into the launch tube as needed in the underwater launch configuration. The canister can simply be dropped in and the bladders inflated. For missile restraint, inflatable pads can replace the sabots. In this case, the invention behaves more like a snubber, but without the complicated linkages and the excessive load transfer into the missile.